The invention relates to a composition comprising a tanning agent for tanning hides and/or pelts. Furthermore, the invention also relates to a method for tanning hides and/or pelts in order to produce leather. More particularly, the invention relates to a composition and a method for pretanning and/or retanning, preferably for pretanning.
Numerous compositions and methods of the above-mentioned type are already known. Tanning, and in particular pretanning, of hides and/or pelts using aldehydic tanning agents is generally known and is used commercially for example in the so-called “wet white” method. The aldehydic tanning agents primarily used in this case are formaldehyde, propionaldehyde, glyoxal, and most frequently, glutaraldehyde.
A significant drawback of these known compositions and methods based on use of the above-mentioned tanning agents, however, is that the tanning agents exhibit excessively high reactivity with the proteins of the hide to be tanned. Frequently, therefore, in particular in the case of relatively thick hides and/or pelts, the penetration of the tanning agents into deeper layers of the hide to be tanned and/or the pelt to be tanned is insufficient. This can lead to uneven tanning, which can negatively affect the quality of the leather produced.
A further drawback of known compositions and methods of the above type that are based on the use of these tanning agents is that aldehydic tanning agents generally have extremely high toxicity and a pungent odor. However, it is often impossible with known compositions and the methods based thereon to avoid breathing aldehydic vapors and coming into direct contact with these aldehydic tanning agents, thus exposing persons who use these agents for tanning hides and/or pelts to an increased health hazard. In this connection, there is therefore a need to improve occupational safety in tanning with aldehydic tanning agents.